NAME
Text::TabularDisplay - Display text in formatted table output
SYNOPSIS
use Text::TabularDisplay;
my $table = Text::TabularDisplay->new(@columns);
$table->add(@row)
while (@row = $sth->fetchrow);
print $table->render;
+----+-----------+
| id | name |
+----+-----------+
| 1 | Tom |
| 2 | Dick |
| 3 | Harry |
+----+-----------+
DESCRIPTION
Text::TabularDisplay simplifies displaying textual data in a table. The
output is identical to the columnar display of query results in the
mysql text monitor. For example, this data:
1, "Tom Jones", "(666) 555-1212"
2, "Barnaby Jones", "(666) 555-1213"
3, "Bridget Jones", "(666) 555-1214"
Used like so:
my $t = Text::TabularDisplay->new(qw(id name phone));
$t->add(1, "Tom Jones", "(666) 555-1212");
$t->add(2, "Barnaby Jones", "(666) 555-1213");
$t->add(3, "Bridget Jones", "(666) 555-1214");
print $t->render;
Produces:
+----+---------------+----------------+
| id | name | phone |
+----+---------------+----------------+
| 1 | Tom Jones | (666) 555-1212 |
| 2 | Barnaby Jones | (666) 555-1213 |
| 3 | Bridget Jones | (666) 555-1214 |
+----+---------------+----------------+
METHODS
Text::TabularDisplay has four primary methods: new(), columns(), add(),
and render(). new() creates a new Text::TabularDisplay instance;
columns() sets the column headers in the output table; add() adds data
to the instance; and render() returns a formatted string representation
of the instance.
There are also a few auxilliary convenience methods: clone(), items(),
reset(), populate(), and paginate().
new A Text::TabularDisplay instance can be created with column names
passed as constructor args, so these two calls produce similar
objects:
my $t1 = Text::TabularDisplay->new;
$t1->columns(qw< one two >);
my $t2 = Text::TabularDisplay->new(qw< one two >);
Calling new() on a Text::TabularDisplay instance returns a clone of
the object. See the clone entry in the Text::TabularDisplay manpage.
columns
Gets or sets the column names for an instance. This method is called
automatically by the constructor with any parameters that are passed
to the constructor (if any are passed).
When called in scalar context, columns() returns the *number of
columns in the instance*, rather than the columns themselves. In
list context, copies of the columns names are returned; the names of
the columns cannot be modified this way.
add Takes a list of items and appends it to the list of items to be
displayed. add() can also take a reference to an array, so that
large arrays don't need to be copied.
As elements are processed, add() maintains the width of each column
so that the resulting table has the correct dimensions.
add() returns $self, so that calls to add() can be chained:
$t->add(@one)->add(@two)->add(@three);
render
render() does most of the actual work. It returns a string
containing the data added via add(), formatted as a table, with a
header containing the column names.
render() does not change the state of the object; it can be called
multiple times, with identical output (including identical running
time: the output of render is not cached).
If there are no columns defined, then the output table does not
contains a row of column names. Compare these two sequences:
my $t = Text::TabularDisplay->new;
$t->add(qw< 1 2 3 4 >);
$t->add(qw< 5 6 7 8 >);
print $t->render;
$t->columns(qw< one two three four >);
print $t->render;
# Example 1 output
+---+---+---+---+
| 1 | 2 | 3 | 4 |
| 5 | 6 | 7 | 8 |
+---+---+---+---+
# Example 2 output
+-----+-----+-------+------+
| one | two | three | four |
+-----+-----+-------+------+
| 1 | 2 | 3 | 4 |
| 5 | 6 | 7 | 8 |
+-----+-----+-------+------+
render() takes optional $start and $end arguments; these indicate
the start and end *indexes* for the data to be rendered. This can be
used for paging and the like:
$t->add(1, 2, 3)->add(4, 5, 6)->add(7, 8, 9)->add(10, 11, 12);
print $t->render(0, 1), "\n";
print $t->render(2, 3), "\n";
Produces:
+-------+--------+-------+
| First | Second | Third |
+-------+--------+-------+
| 1 | 2 | 3 |
| 4 | 5 | 6 |
+-------+--------+-------+
+-------+--------+-------+
| First | Second | Third |
+-------+--------+-------+
| 7 | 8 | 9 |
| 10 | 11 | 12 |
+-------+--------+-------+
As an aside, note the chaining of calls to add().
The elements in the table are padded such that there is the same
number of items in each row, including the header. Thus:
$t->columns(qw< One Two >);
print $t->render;
+-----+-----+----+
| One | Two | |
+-----+-----+----+
| 1 | 2 | 3 |
| 4 | 5 | 6 |
| 7 | 8 | 9 |
| 10 | 11 | 12 |
+-----+-----+----+
And:
$t->columns(qw< One Two Three Four>);
print $t->render;
+-----+-----+-------+------+
| One | Two | Three | Four |
+-----+-----+-------+------+
| 1 | 2 | 3 | |
| 4 | 5 | 6 | |
| 7 | 8 | 9 | |
| 10 | 11 | 12 | |
+-----+-----+-------+------+
OTHER METHODS
clone()
The clone() method returns an identical copy of a
Text::TabularDisplay instance, completely separate from the cloned
instance.
items()
The items() method returns the number of elements currently stored
in the data structure:
printf "There are %d elements in \$t.\n", $t->items;
reset()
Reset deletes the data from the instance, including columns. If
passed arguments, it passes them to columns(), just like new().
populate()
populate() as a special case of add(); populate() expects a
reference to an array of references to arrays, such as returned by
DBI's selectall_arrayref method:
$sql = "SELECT " . join(", ", @c) . " FROM mytable";
$t->columns(@c);
$t->populate($dbh->selectall_arrayref($sql));
This is for convenience only; the implementation maps this to
multiple calls to add().
NOTES / ISSUES
Text::TabularDisplay assumes it is handling strings, and does stringy
things with the data, like legnth() and sprintf(). Non-character data
can be passed in, of course, but will be treated as strings; this may
have ramifications for objects that implement overloading.
Newlines contained within the data ruin formatting. This is consistent
with the software that this module is emulating (the mysql command line
client), but only because this was easier to implement.
Currently, this:
my $t = Text::TabularDisplay->new("id", "text");
$t->add(1, "This is my text.\nThere are many like it, but this one is mine.");
print $t->render;
renders as this:
+----+----------------------------------------------------------------+
| id | text
|
+----+----------------------------------------------------------------+
| 1 | This is my text.
There are many like it, but this one is mine. |
+----+----------------------------------------------------------------+
I would like it to render like so:
+----+----------------------------------------------------------------+
| id | text |
+----+----------------------------------------------------------------+
| 1 | This is my text. |
| | There are many like it, but this one is mine. |
+----+----------------------------------------------------------------+
Patches welcome, of course. ;)
The biggest issue, though, is that this module duplicates a some of the
functionality of Data::ShowTable. Of course, Data::ShowTable is a large,
complex monolithic tool that does a lot of things, while
Text::TabularDisplay is small and fast.
VERSION
$Id: README,v 1.6 2002/10/28 20:14:54 dlc Exp $
AUTHOR
darren chamberlain